Occupational Ergonomics 10 (2011) 1–11 1 DOI 10.3233/OER-2011-0188 IOS Press The biomechanical characteristics and physiological cost of three standardized pulling tasks Grant A. Handrigan a , Geoffrey A. Power a , Scott N. MacKinnon a,b and Fabien A. Basset a,∗ a School of Human Kinetics and Recreation, Memorial University of Newfoundland, St. John’s, NL, Canada b SafetyNet INCO Innovation Centre, Memorial University of Newfoundland, St. John’s, NL, Canada Abstract. Purpose: The purpose of this study was to investigate the biomechanical characteristics and physiological cost of three standardized pulling tasks. 12 female and 17 male subjects participated in the study. The subjects were instructed to pull a load at three different heights (hip, shoulder, eye – anatomical landmarks defined the end of a pull) at a rate of ten pulls per minute, for a period of ten minutes (one hundred total pulls). The pulls were sub-maximal and chosen to represent a task during a typical 8 hour workday. Statistics: ANOVA statistical analyses with Bonferroni pairwise comparisons were performed to determine significance. Results: Statistical significance was obtained for energy expenditure ( ˙ E), sagittal displacement and twisting velocity. Hip pulling ˙ E was lower than shoulder pulling ˙ E (p = 0.046) and eye pulling ˙ E (p = 0.002) by 7% and 11%, respectively. Hip pulling involves less sagittal displacement than shoulder (p = 0.004) and eye (p = 0.001) by 37% and 46%, respectively. Finally, twisting velocity at hip (p = 0.042) and shoulder (p = 0.006) pulling were 30% and 36% higher than twisting velocity at eye pulling. Conclusion: Physiological data combined with biomechanical data provide a comprehensive description of the demands associated with this standardized pulling task. This combined information assists in risk factor identification and intervention design for tasks involving repetitive upper limb movements. Keywords: Pulling, energy expenditure, trunk kinematics, repetitive motion, fatigue 1. Introduction Manual materials handling (MMH) is a major component of many industrial occupations, and a significant risk factor for musculoskeletal injuries [1]. Promoting movement ef ficiency to reduce overuse is important in manual materials handling, specifically to reduce the amount of repetitive work and limit overuse injuries as it is a risk factor for injury [2,3]. Occupational ergonomic interventions attempt to reduce the risk of injury and mitigate economic loss. Promoting movement efficiency and low risk activities are important steps in accomplishing this goal; however, this requires a thorough understanding of the risk factors and proper implementation of appropriate ergonomic design factors. With an increase in the use of assistive devices to perform MMH, it is also important not to redirect the strain from one body ∗ Address for correspondence: Fabien A. Basset, School of Human Kinetics and Recreation, Memorial University, St. John’s, NL, A1C 5S7, Canada. Tel.: +1 709 864 6132; E-mail: fbasset@mun.ca. 1359-9364/11/$27.50  2011 – IOS Press and the authors. All rights reserved